Apparatus for burning solid fuel



Jan. 17, 1956 M. BIRKNER 2,730,998

APPARATUS FOR BURNING SOLID FUEL M. BIRK NE y/WMW'VM ATTORNEYS INVENTORJan. 1956 M BIRKNER 2,730,998

APPARATUS FOR BURNING SOLID FUEL INVENTOR M. BIH/(NEW ATTORNEYS UnitedStates Patent APPARATUS FDR BURNING SOLID FUEL Max Birkner,Koln-Dellbruck, Germany Application June 19, 1950, Serial No. 168,925

Claims priority, application Germany July 11, '1949 14 Claims. (Cl.122-4) This invention relates to improvements in or modifications of afurnace operating in accordance with the method of burning solid fueldescribed and claimed in co-pending application Serial Number 123,515tiled October 25, 1949.

In theabove-referred to co-pending application I have described a methodof burning solid fuel in a vertically extending combustion zone whichincludes delivering fuel by gravity from substantially midway of theheight of the zone upon the front portion of a tire bed moving on atravelling grate travelling from front to rear of the zone andeincludingthree longitudinally aligned portions. Oxidizing medium is introducedfrom beneath the bed under all the portions and the pressure of theintroduced medium being increased successively from front to rear sothat the coal is fluidized under the middle portion and under therearmost portion incandescent particles are picked upl and flung fromthe bed toward the front of the zone to intermingle with the incomingfuel.

Accordingly, the present invention has for an object to improve theconstruction and operation of a furnace of the aforedescribed characterand more specifically provides partition means within the furnace spaceto separate the furnace space into a iire box region or zone and anupper region or zone to constitute a radiation section.

More specifically the partition means includes a central opening ofcircular cross section through which combustion gases are dischargedinto the radiation section of the boiler or furnace. This partition, incombination with tertiary air tuyeres as described in the aboveidentified co-pending application, providing a cyclone action toseparate fuel and fume-borne ash particles.

A more specific object is to provide a depending circular sleeveextending downwardly from the edges of the opening in the partition andan additional specific object is to provide a diffuser outlet extendingupwardly into the radiation section of the boiler or furnace.

An additional specific object is to provide ash-deflect@ ing surfacessuperjacent each row of tuyeres.

While it is known in the art to provide cyclone-type furnaces as, forexample, in Patent 2,357,302 to Kerr the present arrangement affordsspecific improvements thereover and in combination with a furnace inwhich solid fuel is initially burnt on a travelling grate and as theoperation proceeds with fuel lluidization and elevation of particles offuel from the rear of the grate, a burning -in suspension effect existsin the zone or region of the furnace or fire box that is beneath thepartition. in connection with this application, solid fuel as utilizedis generally larger in particle size than pulverized fuel or coal dust,although it may contain some of the latter.

Further and more specific objects and features of the invention are aarent from the followin descri tion P when taken in connection with theaccompanying drawfurnace that embodies the invention,

2,730,998 Patented Jan. 1 7, 195.6

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Figure 2 is a cross-sectional view taken along lines 2 2 of- Figure l;

Figure 3 is a View similar to Figure l but illustrating a modied form offurnace construction, and

Figure 4 is a cross-sectional view taken along. lines 4-4 of Figure 3.

In the drawings like reference numeralsdenote the same orequivalentparts. The furnace constructed in accordance with this inventionincludes wall means that define a vertically disposed combustion zoneand a radiation section or zone coaxially thereabove. At the bottom ofthe combustion zone is a travelling grate, denoted diagrammatically atn, the grate traveling from front to rear of the combustion zone andbeing adapted to support andl move a fire bed. The front wall of thefurnace .includes a lower portion b so related with respect to an upperportion of the front wall as to provide a fuel inlet passage or orificei. A conveyor h forwards al1 fuel through the inlet passage, so that thefuel falls by gravity upon the grate at the front portion of thecombustion zone.

As set forth in complete detail in my above referred to application, theregion beneath the grate, denoted generally at k, includes threelongitudinally aligned por'- tions through which oxidizing medium isintroduced, the oxidizing medium flowing upwardly through the fire bedon the grate with the pressure of the introduced medium increasingtoward the rear of the grateV so as to :luidize fuel upon the middleportion of the, grate and to elevate fuel and incandescent particlesfrom the rear of the grate. Additional oxidizing medium is introducedthrough nozzles n which project Vthrough the rear Wall c at a levelabove the grate. This additional medium entrains and projects theelevated fuel and incandescent particles across the bed to the front ofthe combustion zone so that they are intermingled with the incomingfuel. Protecting tube walls e are embodied in the combustion zone and inthe radiation section and a shaft or channel g is disposed at the rearof the grate for completing combustion of particles of coke adhering tothe slag.

The combustion space or zone of the furnace includes a portion UFconstituting a lower fire box that extends immediately above the grateand a portion OF constituting an upper fire box. A plurality of spaced,superposed tiers of vtuyeres s, t and u project through the walls wdefining the upper iire box OF. These tuyeres are directed, as indicatedin Figure 2, to provide a whirling action about the vertical axis of theupper fire box. The tuyeres constitute means for furnishing a tertiarysupply of oxidizing medium.

The region above the upper fire box is a water tube ined radiationsection R. In accordance with the invention, this section is separatedfrom the upper tire box OF, where the gases are subjected to thewhirling action, To accomplish this separation or division, there isprovided a horizontal partition arranged above the uppermost bank Vortier of tuyeres. The horizontal partition has a central circular openingtherein through which gases are discharged into the radiation space ofthe boiler. lt is convenient to extend the edge of this openinffdownwardly so as to form a cylindrical sleeve. in this way in the upperpart of the furnace a cyclone action arises and a good separation offuel and fume-borne ash particles is effected so that under certainconditions a fume filter and a conduit for returning the fume-borne ashparticles separated therein to the furnace can be omitted. In thedrawings V is the partition and z is the downwardly extendingcylindrical sleeve, and in both examples both the partition and thesleeve are shown as of tubular construction.

According to the invention it is further found advantageous to make Vtheupper part of the furnace of cylin- Vis located between the lire boxes.

vided that bound the upper radiation section that is aboveV Ythe upperVfire box and tuyeres arranged in a plurality of drical folrnation as aresult of which a cyclone is formed, which cyclone has a differentaction however from that kof a previous proposal in which a cyclonehaving a horizontal axis or an axis very slightly inclined to thehorizontal, acts as combustion and ash-melting zone."

The transition from the cylindrical part CF of the upper irebox to arectangular opening at the bottom over the grate necessitates tubesystems x1, x2, x3 and x4 at the corners as shown in Figure 4.

In order to utilize the whirling energy for the ow through the boiler,according to the invention the com bustion gases are discharged througha diffuser-like enlargement expanding to the cross-section of theradiation space of the boilerwhich is situated above the upper fire box.Figure 3 shows at W such a diffuser-like enlargement of the short'cylindrical sleeve z which opens out into the radiation space of theboiler, and in the example this diffuser is shown of tubularconstruction.

The partitioning oif of the upper part of the furnace andthe furtherimprovements described, bring about a considerable increase in theVeiciency of the whole combustion process which can be still furtherincreased by forced working, that is by working the furnace and the vadjoining boiler heated thereby under pressure, in the manner known perse.

Under these conditions owing to the reduction by theV partition of thedischarge passage for the combustion gases the furnace temperatures mayeasily exceed the ash melting point. Accordingly there is a danger ofthe Ytertiary air supplyrtuyeres s, t, 1.a leading into theupper:

furnace space being clogged upY by slag formation. To avoid this danger,according to the invention downwardly and inwardly inclinedash-deflecting surfaces shown at y in Figure 3 are arranged above thetuyeres s, t and u respectively. These deecting surfaces extend over thewhole circumference of the upper furnace space. For the reason thatthese surfaces extend over the whole of the circumference, their inneredges have aV great peaccumulating around the openings of the tertiaryair supply tuyeres. Moreover, down-flowing ash could possibly pass overthe wall areas between the inlets for the tertiary air supply tuyeresand might lead Yto heavy slag deposits on these areas which are oc upiedby Vradiation tubes. According to the invention it is advantageous towiden these deilecting surfaces upwardly so that the lowermost openingsfor the tertiary air supply are coveredby the narrowest deilectingsurface and the ippermost open-y ings are covered by the widestdeflecting surfaces, as a result of which the deflected ash particlesare distributed over a wide area. This widening is shown in Figure 3.

To avoid interference with the whirling action due to these deflectingsurfaces according to the invention it is furthermore advantageous toconstruct them as indicated in Figure 3 as continuous helicalconvolutions in the same direction as the whirling action.

It is believed clear, therefore, that the present invention provides ina boiler furnace, the combination of wall means that deiine a verticallydisposed combustion zone and a radiation section coaxially thereabovc. Atraveling grate a is movable from front to rear in the lower portion ofthe combustion zone. Means are provided for forwarding fuel to fall'bygravity upon the grate inthe front portion of the zone including thefuel conveyor h anda fuelV inlet orifice in the front wall that is abovethe front portion of the grate. It is to be noted that the combustionzone includes one portion providing a lower re The fuel inlet orificeWater tubes are probox UF and an upper fire box GF.

for injecting combustion supporting medium such as air thereinto. Asreferred to previously, thesetuyeres are directed so as to provide awhirling action about the vertical axis of the fire box. Water tubes arearranged to provide a horizontal partition located above the tuyeres fordividing the upper fire box from the radiation section at a levelclosely super-jacent the tuyeres. has a central opening therein topermit discharge of combustion gases into the radiation section. A'shortcylindrical sleeve extends downwardly from the partition from the edgeof the opening therethrough into the upper re box. Furthermore, rthissleeve also extends above the partition into the radiation section andincreases in di-V arneter upwardly to define a Vdiffusing means throughwhich gases are discharged into the' radiation section.

All the walls of the furnace structure describedY are formed by tubesystems such asV e through which kwater is positively passed orcirculated, and noV detailed description of this is necessary.

I claim: Y v l. In a boiler furnace, the combination of wall meansdeiining a vertically disposed combustion zone and a radiation sectioncoaxially thereabove, a traveling grate movable from front to rear inthe lower portion of said zone,

said wall means including a front'wall having fuel inletV fuel inletorifice being disposed between the tire boxes,

water tubes bounding the radiation section above the upper fire box,tuyeres extending through the walls Yof the upper fire box for injectingair thereinto, said tuyeres Y being so directed as to provide a whirlingof injected airY and `furnace gases about the vertical axis of the rebox, a horizontal partition above' the tuyeres for dividing the upper reboxV from the radiation section at a level closely superjacent thetuyeres, and said partition having a central opening therein for thedischarge of combustion gases into said radiation section. Y p

2. In a boiler furnace, the combination of wall means defining avertically disposed Vcombustion zone and a radiation section coaxiallythereabove, a travelling grate movable from front to rear inthe lowerportion of said zone, said wall means includingV a front Wall having afuel inlet orifice therein above the grate, means for forlower fire boximmediately above said grate and a second portionr providing an upperfire box extending above said lower re box, said fuel inlet orificebeing disposed be tween the lire boxes, water tubes bounding theradiation section above the upper fire box, tuyeres extending throughthe walls of the upperre box for injecting Vair there-V into, saidtuyeres being so directed as to provide a whirling of injected air andfurnace gases about'the vertical axis of the tire box, a horizontalpartition above the tuyeres for dividing the upper fLre boxY from theradiation section at a level closely superjacent the tuyeres, saidVpartition having a central openingtherein for the discharge ofcombustion gases into Vsaid radiation section, and-also including ashort cylindrical sleeve extending downwardly from the edge of theopening of the partition into the upper fire box. l :Y

3. In a boiler furnace as defined in claim 1,' whereinY l the upper firebox is of cylindrical formation.

4. VIn a boiler furnace as defined in claim 1, and further including,circumferential downwardly and inwardlyk inclined ash-deflectingVsurfaces Varranged above said tuyeres. Y

5. In a boiler furnace as defined in claim 4, in which the tuyeres arearranged in a plurality of spaced super- This partition posed rows, adownwardly inclined circumferential ashdeflecting surface above each rowof tuyeres, and the said surfaces defining sets of separate conicalsurfaces each increasing upwardly in diameter and the superposed sets ofsurfaces respectively increasing in slant height from the lowermost tothe uppermost.

6. In a boiler furnace as defined in claim 1, and also including watertubes defining a sloping circumferential ash-deiiecting surface abovethe tuyeres, said last mentioned water tubes each being of contiguoushelical conformation and having their helical axes lying in the surfaceof an inverted cone and following the direction of the whirling actionproduced by said tuyeres.

7. In a boiler furnace, the combination of wall means dening avertically disposed combustion zone and a radiation section coaxiallythereabove, a travelling grate movable from front to rear in the lowerportion of said zone, means for forwarding fuel to fall by gravity uponthe grate at the front portion of said zone, said zone including aportion providing a lower fire box above said grate and an upper firebox supexjacent the lower iire box, said fuel forwarding means includingan inlet orifice between the lire boxes, said inlet orifice being at thefront of the zone, water tubes bounding the upper radiation sectionabove the upper fire box, tuyeres extending into the upper fire box forinjecting air thereinto, said tuyeres being so directed as to provide awhirling action about the vertical axis of the upper fire box, meansproviding a horizontal partition above the tuyeres for dividing theupper fire box from the radiation section at a level closely superjacentthe tuyeres, said partition having a central opening therein, a shortcylindrical sleeve extending downwardly from the edge of the openinginto the upper part of the tire box and said sleeve extending above thepartition into the radiation section and increasing in diameter upwardlyto define a diffusing means through which gases are discharged into theradiation section.

8. In a boiler furnace, the combination of wall means defining avertically disposed combustion zone and a radiation section coaxiallythereabove, said wall means including a front wall, a travelling gratemovable from front to rear in the lower portion of said zone, meansincluding a fuel inlet orifice in the front wall above the grate forforwarding fuel to fall by gravity upon the grate at the front portionof said zone, said zone including a portion providing a lower iire boxabove said grate and an upper fire box superjacent the lower lire box,said fuel inlet orifice being between the lire boxes, water tubesbounding the upper radiation section above the upper tire box, tuyeresextending into the upper fire box for injecting air thereinto, saidtuyeres being so directed as to provide a whirling action about thevertical axis of the iire box, water tubes defining a horizontalpartition above the tuyeres for dividing the upper lire box from theradiation section at a level closely superadjaoent the tuyeres, saidpartition having a central opening therein, water tubes defining a shortcylindrical sleeve extending downwardly from the edge of the openinginto the upper part of the fire box and water tubes extending from saidsleeve above the partition into the radiation section and defining adiffuser of increasing diameter upwardly and outwardly and terminatingwith the uppermost tubes adjacent the water tubes bounding the upperradiation section.

9. In a boiler furnace, the combination as claimed in claim 8 in whichthe tuyeres are arranged in a plurality of spaced superposed tiers andwater tubes defining a sloping circumferential ash-detiecting surfaceabove each tier of tuyeres, said last mentioned water tubes each beingof continuous contiguous helical conformation and having their helicalaxes lying in the surface of an inverted cone and following thedirection of Whirl produced by said tuyeres.

10. A boiler furnace comprising wall means defining a verticallydisposed combustion zone and a radiation section coaxially thereabove,said combustion zone including a iire box the upper part of which is ofcylindrical formation, water tubes bounding the radiation section abovesaid fire box, tuyeres arranged in superposed rows and extending throughthe walls into the upper cylindrical portion of the iire box forinjecting air thereinto, said tuyeres being so directed as to provide awhirling of air and gases about the vertical axis of the fire box, apartition above the uppermost row of tuyeres for dividing the uppercylindrical portion of the tire box from the radiation section at alevel closely superjacent the uppermost row of tuyeres, said partitionhaving a central circular opening therein, a short cylindrical sleeveextending downwardly from the edge of said opening part way into theupper cylindrical portion of the fire box, and means defining adownwardly and inwardly sloping circumferential ash-deflecting surfaceabove each row of tuyeres.

11. A boiler furnace as claimed in claim 10, in which the respectiveash-deflecting surfaces are separate conical surfaces each increasingupwardly in diameter and the slant height of each surface increasingfrom the lowermost to the uppermost surface.

12. A boiler furnace as claimed in claim 11, in which water tubesconstitute each of the said surfaces, said last mentioned water tubes ofeach surface being of contiguous helical conformation and having theirhelical axes lying in the surface of an inverted cone and following thedirection of the whirl produced by said tuyeres.

13. A boiler furnace as claimed in claim 1, in which water tubesconstitute said horizontal partition.

14. In a boiler furnace, the combination of wall means defining avertically disposed combustion zone and a radiation section coaxiallythereabove, a travelling grate movable from front to rear in the lowerportion of said zone, said wall means including a front wall having afuel inlet orifice therein located above the grate, means for forwardingfuel through the inlet orifice to fall by gravity upon the grate at thefront portion of said zone, said zone including a portion providing alower fire box above said grate and an upper tire box superjacent thelower tire box, said fuel inlet oriiice being between the iire boxes,tuyeres extending into the upper lire box for injecting combustionsupporting medium thereinto, said tuyeres being directed so as toprovide a whirling action about the vertical axis of the re box, meansproviding a horizontal partition above the tuyeres for dividing theupper re box from the radiation section at a level closely superjacentthe tuyeres, said partition having a central opening therein, a shortcylindrical sleeve extending downwardly from the edge of the openinginto the upper re box, said sleeve extending above the partition intothe radiation section and increasing in diameter upwardly to dene adiffusing means through which gases are discharged into the radiationsection, and circumferential downwardly and inwardly inclinedash-deecting surfaces arranged above said tuyeres.

References Cited in the tile of this patent UNITED STATES PATENTS1,536,776 Cotton May 5, 1925 1,917,275 Rossman et al. July 1l, 19332,357,302 Kerr et al. Sept. 5, 1944 2,357,303 Kerr et al. Sept. 5, 19442,386,336 Mosshart Oct. 9, 1945 2,483,728 Glaeser Oct. 4, 1949 FOREIGNPATENTS 587,240 Great Britain Apr. 18, 1947

